1. Field of the Invention
Apparatuses consistent with the present invention relate to a serial data receiving apparatus and an electronic apparatus using the same, and more particularly, to a serial data receiving apparatus which receives serial data transmitted from an external device such as a computer, instead of an RS232 integrated circuit (IC).
2. Description of the Related Art
In general, Recommended Standard Number 232 (RS232) interface standards are standards which are used for serial data communications between a computer and its peripherals. Electronic apparatuses such as televisions use an integrated circuit (IC) compatible with RS232 standards in order to upgrade programs or provide after-sales service.
Electronic apparatuses generally have a 9-pin D-SUB connector, through which the electronic apparatus can perform RS232 interfacing with a computer. That is, the electronic apparatus is connected to the computer using a 9-pin D-SUB connector, and an RS232 IC receives serial data transmitted from the computer, and transmits the data to a modem multiplexer (micom) which controls the operation of the electronic apparatus. The operation of receiving serial data of the RS232 IC is briefly described with reference to FIG. 1.
FIG. 1 is a schematic block diagram illustrating a related art serial data receiving apparatus.
In FIG. 1, the RS232 IC functions as an RS232 receiver which receives serial data, and the RS232 receiver 10 includes a level change unit 12, and an inversion unit 14.
The level change unit 12 receives RS232 data, and changes its voltage level to Transistor-Transistor Logic/Complementary Metal-Oxide Semiconductor (TTL/CMOS) voltage level. In other words, the RS232 data are received with a high voltage level of +3 V to +15 V, and with a low voltage level of −15 V to −3 V. The level change unit 12 changes such a voltage level to TTL/CMOS voltage level having +2 V to +5 V and +0.8 V to 0 V.
The inversion unit 14 inverts the data changed to TTL/CMOS voltage level. In more detail, the inversion unit 14 inverts the high voltage level of +2 V to +5 V to the low voltage level of 0 V to 0.8 V, and inverts the low voltage level of +0.8 V to 0 V to the high voltage level of +2 V to +5 V, so that the input data are inverted and output to TTL/CMOS data.
Such an RS232 receiver 10 converts RS232 data into TTL/CMOS data, and transmits the TTL/CMOS data to a micom (not shown). Such functions are performed by an IC which is more expensive than basic elements such as a transistor, a resistor, and a diode, resulting in increased manufacture costs.